This invention relates to emergency evacuation equipment for aircraft. In particular, this invention relates to an inflatable aircraft evacuation slide.
The requirement for reliably evacuating airline passengers in the event of an emergency becomes more important as the size of the aircraft and the number of passengers increases. Emergencies at take-off and landing often demand swift removal of the passengers from the aircraft because of the potential for injuries from fire, explosion, or sinking in water. A conventional method of quickly evacuating a large number of passengers from an aircraft is to provide multiple emergency exits each of which is equipped with an inflatable evacuation slide. As more and more passenger rows are added, more emergency exits and slides are necessary to ensure the safe evacuation of all passengers. Indeed, in order ensure safe evacuation of all passengers, aviation regulations currently require that emergency exit pairs (one door on each side of the aircraft) be no more than 60 feet apart.
A substantial number of passenger seats are normally located directly over the wing section of most commercial aircraft. Therefore, in order to comply with emergency exit regulations it is necessary to locate emergency doors immediately over the aircraft wing. These over-wing emergency exits require passengers to exit the aircraft by stepping out onto the upper surface of the wing in order to make their way to the evacuation slide. Unfortunately, the passenger deck level of most commercial aircraft is often considerably higher than the upper surface of the wings. Emergency exit doors over the wing sections must therefore be located several feet above the wing. Also, the upper wing surface of the aircraft has a substantial pitch. Worse, because the evacuation slide must extend outwardly from the aircraft, the lower xe2x80x9cfootxe2x80x9d end of the slide is obscured by the trailing edge of the wing itself. Accordingly, it is not possible for a disembarking passenger to know whether or not the slide is properly deployed without walking out onto the wing to verify. Thus, evacuating passengers from a wing exit directly onto the wing not only would require the passengers to drop several feet from the exit opening onto a sloping surface, but would require the disembarking passengers to walk to the edge of the wing and peer over the edge to determine that the slide is properly deployed before proceeding down the evacuation slide. Obviously, in an emergency a substantial number of injuries would be possible at such an exit during the hurried departure of the passengers.
Prior art evacuation slides have overcome the emergency-exit-to-wing surface drop and wing slope problems by providing a raised stable walkway that is deployed over the wing to provide a substantially horizontal walkway leading up to the head end of an over-wing evacuation slide. The problems associated with the aircraft wing obscuring the foot end of the evacuation slide, however, have not been adequately addressed. Prior art evacuation slides have relied on the combination of a trained flight attendant and an inflatable pole (sometimes referred to as a xe2x80x9cbarber polexe2x80x9d) to provide a visual indication that the lower end of the evacuation slide has been properly deployed. A prior art evacuation slide having a barber pole indicator is disclosed for example in U.S. Pat. No. 4,333,546 to Fisher. Barber pole visual indicators have a number of disadvantages, including the fact that they use valuable inflation gasses to effect their deployment. Moreover, barber pole visual indicators are not intuitive. Accordingly, if a trained flight attendant is not available to monitor the evacuation, self-disembarking passengers will not know to look for the barber poles to determine the status of the evacuation slide and may attempt to exit the plane before the slide is properly deployed.
Accordingly, what is needed is a readiness indicator for an aircraft evacuation slide that does not consume valuable inflation gasses and would be intuitive to an untrained person.
The present invention comprises an inflatable over-the-wing evacuation slide having a readiness indicator the meaning of which is intuitively obvious to an untrained person. In one embodiment, the slide is provided with an inflatable walkway section projecting from the foot of the wing exit door to a point on the aircraft wing remote from the door. The walking surface section is supported at the point remote from the door such that the walking surface presents a generally flat level surface. The walking surface also includes an inflatable guard rail attached to the side margins of the inflatable walking surface. Attached to the side of the inflatable guard rail in a position that is clearly visible from the aircraft exit doorway is a visual readiness indicator. In one embodiment, the visual readiness indicator comprises a conventional red, octagonal xe2x80x9cstopxe2x80x9d sign that is releasably mounted to the guard rail. The stop sign is removed (or obscured) when the evacuation slide has properly deployed. In the illustrative embodiment, removal of the stop sign is effected by attaching one end of a lanyard to the stop sign and the other end of the lanyard to the toe end of the evacuation slide. As the evacuation slide unfurls, the lanyard is paid out until, at the last stage, when the toe end unfolds the lanyard pulls the stop sign off the guard rail, so that it is no longer visible to a disembarking passenger.